我有一个数据框，其索引行是字符串数据类型。我希望它是数字和排序：
col1 col2
1 25 33
3 35 544
2 24 52
预期：
col1 col2
1 25 33
2 24 52
3 35 544
答案 0 :(得分：3)
首先，使用pd.to_numeric进行转换和分配。
df.index = pd.to_numeric(df.index, errors='coerce')
要按索引对DataFrame进行排序，请调用df.sort_index：
df.sort_index()
col1 col2
1 25 33
2 24 52
3 35 544
如果您想进行就地操作，可以为第二个命令指定inplace=True，或者可以将其传递给管道。
答案 1 :(得分：1)
您可以使用import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.Time;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
public class MySQLDatabaseDemo {
Connection conn = null;
PreparedStatement preparedStatement = null;
public static Connection getConnection() throws Exception {
String driver = "org.gjt.mm.mysql.Driver";
String url = "jdbc:mysql://localhost/databaseName";
String username = "root";
String password = "root";
Class.forName(driver);
Connection conn = DriverManager.getConnection(url, username,
password);
return conn;
}
/**
* @param args [0] = value of "id"
* [1] = value of "name"
* [2] = value of "time_from"
*/
public void insertRowWithTimeDatatype(String[] args) {
String query = "insert into my_table (id, name, timefrom) " +
"values (?, ?, ?)";
DateFormat sdf = new SimpleDateFormat("hh:mm:ss");
Date date = sdf.parse(args[2]);
Time time = new Time(date.getTime());
try {
conn = getConnection(); // getConnection() is YOUR method
preparedStatement = conn.prepareStatement(query);
preparedStatement.setInt(1, Integer.parseInt(args[0]));
preparedStatement.setString(2, args[1]);
preparedStatement.setTime(3, time);
// Execute statement and return the number of rows affected
int rowCount = preparedStatement.executeUpdate();
System.out.println("Number of rows affected: " + rowCount);
} finally {
preparedStatement.close();
conn.close();
}
}
}
和astype
sort_index 或，使用In [833]: df.index
Out[833]: Index([u'1', u'3', u'2'], dtype='object')
In [834]: df.index = df.index.astype(int)
In [837]: df = df.sort_index()
In [838]: df
Out[838]:
col1 col2
1 25 33
2 24 52
3 35 544
In [839]: df.index
Out[839]: Int64Index([1, 2, 3], dtype='int64')
set_index